The present invention relates generally to a method of and a system for altimetry, especially passive distant altimetry of an object.
The method used to measure the height of an object above, for example, ground or sea level will depend on, among other things, the spatial relationship the measurement means has with the object whose height is to be measured. If the measurement means is located at the object, i.e. is airborne, then the height can be measured passively by an air pressure gage or actively by radar means, for example an altimetry radar. On the other hand, if the measurement means is located on, for example, the ground separated from the object, then the height to the object can be measured actively by a simple altimetry radar if located directly underneath the object or if not, by a more complex altimetry radar, as both the distance and elevation to the object of interest has to be measured.
The present invention concerns the measurement of the height from, for example, the ground to an object by measurement means located, for example, arbitrarily on the ground. Such altimetry measurements, as previously mentioned, usually require expensive and complicated equipment such as altimetry radar equipment. An altimetry radar is an active device that transmits radar pulses, which is not always a desirable feature.